1. Field of the Invention
The present invention relates to certain imine-substituted heterocyclic compounds, and methods of treatment and pharmaceutical compositions that utilize or comprise one or more such compounds. Compounds of the invention are particularly useful for the treatment or prophylaxis of neurological injury and neurodegenerative disorders.
2. Background
Nerve cell death (degeneration) can cause potentially devastating and irreversible effects for an individual and may occur e.g. as a result of stroke, heart attack or other brain or spinal chord ischemia or trauma. Additionally, neurodegenerative disorders involve nerve cell death (degeneration) such as Alzheimer's disease, Parkinson's disease, Huntington's disease, Amyotrophic Lateral Sclerosis, Down's Syndrome and Korsakoff's disease.
Therapies have been investigated to treat nerve cell degeneration and related disorders, e.g., by limiting the extent of nerve cell death that may otherwise occur to an individual. See, e.g., N. L. Reddy et al., J. Med. Chem., 37:260-267 (1994); and WO 95/20950.
The compound MK-801 has exhibited good results in a variety of in vivo models of stroke. See B. Meldrum, Cerbrovascular Brain Metab. Rev., 2:27-57 (1990); D. Choi, Cerbrovascular Brain Metab. Rev., 2:105-147 (1990). See also Merck Index, monograph 3392, 11th ed., 1989. For example, MK-801 exhibits good activity in mouse audiogenic tests, a recognized model for evaluation of neuroprotective drugs. See, e.g., M. Tricklebank et al., European Journal of Pharmacology, 167:127-135 (1989); T. Seyfried, Federation Proceedings, 38(10):2399-2404 (1979).
However, MK-801 also has shown toxicity and further clinical development of the compound is currently uncertain. See J. W. Olney et al., Science, 244:1360-1362 (1989); W. Koek et al., J. Pharmacol. Exp. Ther., 252:349-357 (1990); F. R. Sharp et al., Society for Neuroscience Abstr., abstr. no. 482.3 (1992).
It thus would be highly desirable to have new neuroprotective agents, particularly agents to limit the extent or otherwise treat nerve cell death (degeneration) such as may occur with stroke, heart attack or brain or spinal cord trauma, or to treat neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, Huntington's disease, Amyotrophic Lateral Sclerosis, Down's Syndrome and Korsakoff's disease.